1. Field of the Invention
The subject invention pertains to the field of floating bearings and particularly to combinations of fixed bearing and floating bearing assemblies which find application in gyroscopic spin bearings and, particularly, to gyroscopic spin bearings incorporated in control moment gyroscopes or reaction wheel assemblies for use in space vehicles and communication satellites.
2. Description of the Prior Art
U.S. Pat. No. 3,742,769 entitled "Gyroscope" issued July 3, 1973 in the names of J. E. Crutcher and L. P. Davis and assigned to the same assignee as the subject application, discloses a gyroscope particularly adaptable for use in stabilizing space vehicles and satellites. As disclosed therein, a rotor is supported for rotation about its spin axis by a pair of oppositely disposed hubs which are each journaled in a pair of spin bearings. As further disclosed in U.S. application Ser. No. 312,241, now U.S. Pat. No. 3,897,985, entitled "Aligning Means for Bearings", filed Dec. 4, 1972 in the names of L. P. Davis and J. E. Crutcher, one of the pair of bearings may be a floating bearing assembly which includes a rotatable member or shaft coupled to the rotor shell and rotatable about a spin axis. The bearing assembly incorporates a floating bearing cartridge which includes a pair of duplex bearings having inner and outer bearing races and a common outer sleeve assembly which serves to clamp the duplex bearing outer races under a predetermined preload. The outer surface of the bearing cartridge is permitted to translate along the spin axis under changes in ambient operating temperature or pressure differential.
As further disclosed in the referenced application, the bearing assembly may include a pair of perimetrical grooves which have a pair of resilient O-rings disposed therein which maintain the bearing cartridge in alignment with respect to the housing during periods of displacement along the spin axis. The O-rings rotate about their respective annular axis in response to translational displacements of the bearing cartridge along the spin axis while producing only low frictional restraining forces that act on the bearing cartridge.
A modification of the invention disclosed in the above referenced application provides improved operation of the gyroscope in a high vibratory environment by the addition of a fluid in the clearance gap formed between the bearing cartridge, the housing and the spaced O-rings. In this modification a quantity of incompressible viscous fluid is inserted in the gap and retained therein by the spaced O-rings. This configuration provides additional radial damping in a high vibratory environment due to the squeeze film action of the incompressible viscous fluid.
The present invention is an improvement over the modification of the invention disclosed in the referenced patent application by providing means for axial damping the floating bearing operating in a high vibratory environment.